Erratum to: Haploid plants from anther cultures of poplar (Populus × beijingensis)

There is an error in the caption to Fig. 2 in the original publication. The text for figure part 2a actually concerns part 2b and vice versa. The correct caption is shown below. Fig. 2 Plant regeneration from another culture of poplar (P. 9 beijingensis). a Haploid plantlets on rooting medium after 1-month culture. b Diploid plantlets after 2 months of culture in rooting medium. c Triploid plantlet after 2 months of culture in rooting medium. Bars = 1 cm